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11/16/2007 12:29:35 PM EDT
did anyone see the open bolt ar on futureweapons. anyone know who the fire system in it is set up?

futureweapons sucks they forgot to say that the saw takes ar mags
11/16/2007 12:46:59 PM EDT
[#1]
i am not sure if i understand your question but the rifles are made by LWRC.
11/16/2007 12:51:18 PM EDT
[#2]
I don't understand the question either, but it is the LWRC IAR.  And in Semi-auto it fires from a closed bolt.  When the selector is switched to full-auto it fires the 1st round from a closed bolt and all the subsequent rounds are fired from an open bolt.  Once the selector switch is moved to semi or safe the bolt closes.
11/16/2007 12:53:21 PM EDT
[#3]
i jus want to know how it goes from semi closed bolt to full auto open bolt. i want to know how the fire control group is set up.
11/16/2007 12:54:12 PM EDT
[#4]
here is a video of it showing it being fired from an open bolt

youtube.com/watch?v=T-VX4M_jgSk
11/16/2007 1:10:42 PM EDT
[#5]
not an FA guy but what's the advantage of firing FA from an open bolt?
11/16/2007 1:11:31 PM EDT
[#6]
Advantages to an open-bolt system?
11/16/2007 1:20:43 PM EDT
[#7]
Cooling.
11/16/2007 1:22:32 PM EDT
[#8]
Simplicity (may not be a big factor in this design) and air flow for cooling. Also, rounds are not chambered until firing.
Higher rate of fire = hotter chamber = rounds more likely to "cook off" from the heat.
11/16/2007 1:24:03 PM EDT
[#9]
Less chance of a cook-off.

edit: T-money beat me to it
11/16/2007 2:02:02 PM EDT
[#10]

Quoted:
i jus want to know how it goes from semi closed bolt to full auto open bolt. i want to know how the fire control group is set up.


If you want to know the exact mechanics of how it works, you're not going to find that out unless the military adopts the IAR and you enlist and end up with one.  Open-bolt auto and closed-bolt semi out of the same gun is a pretty big deal, and LWRC isn't about to go blabbing about how exactly they accomplished it.
11/16/2007 2:35:38 PM EDT
[#11]
If they patented it, you may be able to do a patent search.

I think MGI was working on the same thing.
11/16/2007 2:40:15 PM EDT
[#12]
this seems like a stupid idea for a combat rifle to me, i understand the concept for better cooling for auto fire and what not, but what happens when you get mud or dirt, or debris thrown into the rifle from any number of things that can occur in a combat enviroment, or when you drop to go prone.
11/16/2007 2:42:53 PM EDT
[#13]
height=8
Quoted:
Cooling.


Ok I get the cooling thing but if you watch the video, they guy keeps looking at his gun to see if he's out of ammo.  When he is out of ammo he doesn't know it until he looks.  Seems like a good way to get killed to me.
11/16/2007 2:51:18 PM EDT
[#14]

Quoted:
this seems like a stuid idea for a combat rifle to me, i understand the concept for better cooling for auto fire and what not, but what happens when you get mud or dirt, or debris thrown into the rifle from any number of things that can occur in a combat enviroment, or when you drop to go prone.


Well open bolt machine gun, and submachine gun, designs have been used for over 100 years, so I'd say the .mil isn't too worried about it.
11/16/2007 5:13:29 PM EDT
[#15]

Quoted:
this seems like a stuid idea for a combat rifle to me, i understand the concept for better cooling for auto fire and what not, but what happens when you get mud or dirt, or debris thrown into the rifle from any number of things that can occur in a combat enviroment, or when you drop to go prone.


I am a machine gunner by trade and when I patrolled or went on a convoy in Iraq I kept my bolt forward, rounds ready on the feed tray. When I need to shoot it was a quick racking of the bolt to lock it to the rear. That kept out all the crap.

That video was cool! IMO you dont need an open bolt M16 rifle.
11/16/2007 5:46:32 PM EDT
[#16]

Quoted:
IMO you dont need an open bolt M16 rifle.


In the opinion of the US Marine Corps, there is a need for something similar to what LWRC is offering.  Otherwise they wouldn't have asked for people to make something like that.
11/17/2007 3:33:12 AM EDT
[#17]
Actually i believe this was already done. Didn't the Johnson LMG of WWII fire closed/open depending on mode of fire?

Could be wrong but I think this was the case. And the Marines that used 'em, loved 'em.
11/17/2007 4:00:44 AM EDT
[#18]
why not just make a rifle out of the M231?
That was open bolt if I remember right.
11/17/2007 9:39:28 AM EDT
[#19]
interesting...though I do see the one posters point about how stuff could get into the action and cause a jam/failure a lot more easily.  open bolt designs still don't make sense to me...and by that I mean how they operate.  does the hammer ride/follow the bolt or is it more of a latch holding the bolt back that drops out of the way when you pull the trigger?
11/17/2007 10:01:43 AM EDT
[#20]
Well, a true open-bolt like the Tommy gun has a fixed firing pin. The bolt is opened prior to firing and the trigger releases it to load and slam-fire. On this combination deal, it has to have exactly the same bolt/firing pin set-up as current M16 in order to fire from the closed bolt. That would mean it needs a disconnector to retard the hammer until the bolt is locked to fire from the open bolt along with another device to let the trigger release the bolt + hammer. I'm not a MG guy but I think this would be correct.
11/17/2007 12:22:36 PM EDT
[#21]

Quoted:
interesting...though I do see the one posters point about how stuff could get into the action and cause a jam/failure a lot more easily.  open bolt designs still don't make sense to me...and by that I mean how they operate.  does the hammer ride/follow the bolt or is it more of a latch holding the bolt back that drops out of the way when you pull the trigger?


All our machineguns are already open bolt so how is this any worse than what is currently being used?  Plus you just flip past semi to safe when you want to move and the bolt closes.  Drop to ground and go to full auto and it will be closed untill you fire and then be open bolt.  The goal is to allow more fire power from a larger portion of the squad without resorting to exchanging riflemen for machine gunners.  You get semi auto accuracy and light weight of a rifle with limited full auto machinegun ability in one package.  A SAW will not be as accurate or as lightweight, a rifle not able to fire as much full auto.
11/17/2007 1:16:33 PM EDT
[#22]
wha it failed to mention is that a 30rnd mag goes pretty quick...vs a 100/200rnd SAW belt
11/17/2007 1:21:20 PM EDT
[#23]

Quoted:
Actually i believe this was already done. Didn't the Johnson LMG of WWII fire closed/open depending on mode of fire?

Could be wrong but I think this was the case. And the Marines that used 'em, loved 'em.


The FG42 is one that comes immediately to mind as firing closed-bolt semi, open-bolt auto.  The bolt carrier had two notches, one front and centre, one to the rear and side.
The selector lever acted to move the sear side to side.

When the selector was set to semi, the sear was off-centre, and engaged the rear sear notch on the carrier, so the carrier was mostly forward and the bolt locked.  Pulling the trigger dropped the carrier, which went forward the last few mm, and a ledge on the carrier struck the back of the firing pin, driving it forward to fire the rifle.

When the selector was set to full, the sear was centered, and engaged the forward notch on the carrier so it was held almost all the way back and the bolt was open.  Pulling the trigger dropped the carrier and it slammed forward, stripping and chambering a round, locking the bolt and striking the firing pin in one smooth motion.
11/17/2007 5:04:06 PM EDT
[#24]
The Colt M231 Firing Port Weapon fired from an open bolt at about 1000 rpm.  This was used in the ballports of the early Bradley A0 & A1 vehicles before the slab armor was added to the sides of the vehicle.  Now  only the BFV ramps have ballports.
11/18/2007 10:03:33 AM EDT
[#25]

Quoted:
this seems like a stupid idea for a combat rifle to me, i understand the concept for better cooling for auto fire and what not, but what happens when you get mud or dirt, or debris thrown into the rifle from any number of things that can occur in a combat enviroment, or when you drop to go prone.


Dust cover?

Now you know why.
11/18/2007 10:05:23 AM EDT
[#26]

Quoted:
why not just make a rifle out of the M231?
That was open bolt if I remember right.


The M231 doesn't have a semi mode, does it?

Semi accuracy has never been very good with open bolt for aimed fire.
11/18/2007 10:23:56 AM EDT
[#27]
Light machineguns and infantry rifles should not be mixed. Doing so means that it will not do either job well.

I can't buy it and as of a few years back I don't have to worry about ever being issued one. So I really don't care.
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